Constipation is a common problem among oncology patients and requires careful assessment. Use of validated instruments is important to improving its management. The aim of this study was to validate the Italian translation of the Constipation Assessment Scale (CAS). To test construct validity, patients and apparently healthy adults were asked to complete the CAS. The results indicated that there was a significant difference between the median CAS of the patient group and that of the apparently healthy group. Test-retest reliability was very high (r=0.96; P=0.0001), and the internal consistency as assessed by Cronbach's alpha was 0.768. These findings suggest that the Italian CAS can be used in clinical practice to document the presence and severity of constipation in cancer patients. However, further studies should be conducted in a larger sample of patients to confirm the results.